I understand Rootgrow is being recommended by sellers for almost everything, but its not essential by any means, is quite expensive and plants will grow perfectly well without it. No idea if it would help a magnolia, but is usually used at planting time in the hole, not after planting, and is of great use for roses being planted in an area which has grown roses before, which is certainly when I'd use it.

hi thanks ... my dad bought me some. magnolia is still in its pot as up to now havent been able to get any one help me plant it but we planting it this week ... friend gave me a apple tree and a pear tree and we used it in the planting hole maybe its not needed but it may make for a happy plant . will remember to use it when i buy roses in the autumn .... thanks so much alison